Use the formula method to solve the inverse matrix of the following matrix A, A = 1 4 0 5 2 1 2 3 3

Use the formula method to solve the inverse matrix of the following matrix A, A = 1 4 0 5 2 1 2 3 3

The first step is to find the adjoint matrix A *
The second step is to find the value | a | of the determinant corresponding to matrix A
In the third step, the inverse matrix of matrix A = a * × (1 / | a |)

The inverse matrix a Λ - 1 of the following matrix A is obtained by using the elementary row transformation method: the first row (3.2.0.0), the second row (4.5.0.0), the third row (0.0.4.1) and the fourth row (0.0.6.2)

（5/7 -2/7 0 0）;(-4/7 3/7 0 0 );(0 0 1 -1/2);(0 0 -3 2);

Circle and equation (15 17:28:31)
The equation for finding a circle tangent to the straight line y = x, with the center of the circle on the straight line y = 3x and the chord length of 2 root sign 2 cut by the Y axis

Let the center of the circle be (a, 3a) and the radius be r, then the circle is (x-a) ^ 2 + (y-3a) ^ 2 = R ^ 2, because the circle is tangent to the straight line y = x, then the distance from the center of the circle to the straight line D = | a-3a | / radical 2 = radical 2 * | a | = R, so the circle is (x-a) ^ 2 + (y-3a) ^ 2 = R ^ 2 = 2A ^ 2, let x = 0, that is, a ^ 2 + (y-3a) ^ 2 = 2A ^ 2 is reduced to y ^ 2-6ay + 8A ^ 2 = 0, because the circle is cut by the Y axis

In the equation 1 / 6 = 1 / () + 1 / (), fill in proper positive integers in the brackets to make the equation hold. There are several different ways to fill in

1/6=1/(7)+1/(42)
1/6=1/(8)+1/(24)
1/6=1/(9)+1/(18)
1/6=1/(10)+1/(15)
1/6=1/(12)+1/(12)

Solving binary linear equations 11 + X + 49 + X-Y = y, y-29 + X + y-31 = y

30+x-y=0
3y+x-60=0
y=45/2
x=15/2

[2sin130 & ordm; + sin100 & ordm; (1 + radical 3tan370 & ordm;)] / radical (1 + cos10 & ordm;)

Answer: 2 [2sin130 & ordm; + sin100 & ordm; (1 + root 3tan370 & ordm;)] / root (1 + cos10 & ordm;) = [2sin50 & ordm; + cos10 & ordm; (1 + root 3tan10 & ordm;)] / root (1 + cos10 & ordm;) = [2sin50 & ordm; + cos10 & ordm; + root 3sin10 & ordm;] / root

5 times of a number is 7 less than 80 0.5, and the solution of the equation is used to solve this number

Let this number be X
80×0.5-5x=7
5x=33
x=6.6

Mother cut 2 / 3 of a watermelon to Xiaojun. Xiaojun ate only 1 / 4 of it. How many parts of the whole watermelon did Xiaojun eat?

2/3*1/4=1/6

In the plane rectangular coordinate system, there are two points a (- 2,2), B (3,2), C on the coordinate axis. If △ ABC is a right triangle, the points satisfying the condition have ()
A. 1 B. 2 C. 4 d. 6

The ordinates of a and B are equal, ab = 3 - (- 2) = 5. ∵ C is a point on the coordinate axis. A point can be obtained by passing through point a and perpendicular to X axis, and a point can be obtained by passing through point B. taking AB as the diameter, the circle can intersect with the coordinate axis at 4 points. ∵ according to the circular angle of diameter is 90 °, there are 4 points meeting the conditions, which are C, D, e, H

What's 15 times 40

200/3